Songs, genetics, and morphology: revealing the taxonomic units in the European Cicadetta cerdaniensis cicada group, with a description of new taxa (Hemiptera: Cicadidae)

Recent acoustic studies have revealed that Cicadetta montana (Scopoli, 1772), which was once thought to be a single widespread Palaearctic cicada species, is actually a complex of many taxa. Although some song patterns are very distinct, others comprise groups of closely related species, as in the case of Cicadetta cerdaniensis Puissant & Boulard, 2000, Cicadetta cantilatrix Sueur & Puissant, 2007, and Cicadetta anapaistica Hertach, 2011. Seven spatially or behaviourally isolated metapopulations belonging to this song group from Italy and Switzerland were detected and investigated using acoustic, molecular, and morphological methods. Taxonomic decisions in this group are challenging because of a lack of truly diagnostic morphological characters, variously coloured morphs, qualitatively intermediate song patterns in contact zones, and strong temperature dependence of song-duration characters. Molecular genetic studies suggest rapid speciation resulting in incomplete lineage sorting and introgression. It is only by using multiple sources of data that species can be delimited. The new species Cicadetta sibillaesp.nov. and the new subspecies Cicadetta anapaistica lucanassp.nov. were described using the microstructure of the male calling songs. Cicadetta sibillaesp.nov. occurs from southern Switzerland to central Italy, and is the most abundant cicada in the Northern Apennine. Cicadetta anapaistica lucanassp.nov. is endemic to a small southern Italian distribution range, and seems to be threatened by habitat loss and fragmentation. There is strong evidence that current distribution patterns and phylogenetic relationships of the Cicadetta cerdaniensis group are linked to speciation events in Pleistocene glacial refugia in the Italian, Iberian, and Balkan peninsulas.(c) 2015 The Linnean Society of London